Guava – LongMath.checkedPow方法与实例
checkedPow(long b, long k)是Guava的LongMath类的一个方法,它接受两个参数b和k,用来寻找b的k次方.
语法:
public static long checkedPow(long b, long k)
参数: 该方法接受两个参数,b和k。参数b被称为base,它被提高到k次方.
返回值: 该方法返回b的k次方.
异常: 如果b的k次方在有符号长运算中溢出,方法checkedPow(long b, long k)会抛出算术异常.
下面的例子说明了上述方法的实施情况:
示例1:
// Java code to show implementation of
// checkedPow(long b, long k) method of
// Guava's LongMath class
import java.math.RoundingMode;
import com.google.common.math.LongMath;
class GFG {
// Driver code
public static void main(String args[])
{
long b1 = 5;
int k1 = 7;
// Using checkedPow(long b, long k) method
// of Guava's LongMath class
long ans1 = LongMath.checkedPow(b1, k1);
System.out.println(b1 + " to the "
+ k1 + "th power is: "
+ ans1);
long b2 = 19;
int k2 = 4;
// Using checkedPow(long b, long k) method
// of Guava's LongMath class
long ans2 = LongMath.checkedPow(b2, k2);
System.out.println(b2 + " to the " + k2
+ "th power is: "
+ ans2);
}
}
输出:
5 to the 7th power is: 78125
19 to the 4th power is: 130321
示例2:
// Java code to show implementation of
// checkedPow(long b, long k) method of
// Guava's LongMath class
import java.math.RoundingMode;
import com.google.common.math.LongMath;
class GFG {
static long findPow(long b, int k)
{
try {
// Using checkedPow(long b, long k) method of
// Guava's LongMath class
// This should raise "ArithmeticException" as
// b to the kth power overflows in
// signed long arithmetic
long ans = LongMath.checkedPow(b, k);
// Return the answer
return ans;
}
catch (Exception e) {
System.out.println(e);
return -1;
}
}
// Driver code
public static void main(String args[])
{
long b = 20;
int k = 25;
try {
// Function calling
findPow(b, k);
}
catch (Exception e) {
System.out.println(e);
}
}
}
输出:
java.lang.ArithmeticException: overflow
参考:https://google.github.io/guava/releases/20.0/api/docs/com/google/common/math/LongMath.html#checkedPow-long-int-